The Internet comprises a vast number of computers and computer networks that are interconnected through communication links. The interconnected computers exchange information using various services. In particular, a server computer system, referred to herein as an email server, web server, server device, server, or the like, may receive connections through the Internet from one or more remote client computer systems, and may send to or receive from the remote client computer system one or more email messages. Further, the email server may connect with various other email servers or other server types throughout the Internet to effect the delivery of email messages either through sending outgoing email messages, receiving incoming email messages, or propagating email messages along to other email servers.
When an outgoing email message is to be sent, an email server checks the email address domain in the recipient address (e.g., “example.com” in the example email address “username1@example.com”) and queries a Mail Exchange (MX) record at a Domain Name Service (DNS) server to determine where to send the email message having that particular address domain. The MX record contains message exchange information and points to an “A” record in the DNS server, the A record containing at least one proper Internet Protocol (IP) address of the recipient email server to which the email message is to be sent. The DNS server will respond with at least one of the IP addresses in the A record. The email server then sends the email message to the recipient email server located at that IP address. The recipient email server for that particular recipient domain (indicated by the MX record), and more specifically, the Mail Transfer Agent (MTA) of the recipient email server, is subsequently tasked with determining the particular username or email inbox to deliver the received email message. Notably, the MX record does not distinguish between individual usernames or specific addresses within a particular domain.
Though suitable for some purposes, such a process does not meet the needs of all applications and settings because the structure of the MX record within the DNS allows only for a domain-level determination of where to send an email message. In this process it is not possible to establish multiple email addresses utilizing a single email domain where the multiple email addresses are spread across different email service providers. For example, a first email address, (e.g., username1@example.com) cannot be serviced by a first email service provider while a second email having the same domain (e.g., username2@example.com) is serviced by a second email service provider. Thus, organizations and individuals are limited to utilizing a single email service provider to service all email address or usernames within their domain.